DENVER–The youngest members of the Giants roster are charged with igniting change, showcasing potential and providing hope that the future of the franchise wont look as bleak as the present.

Alen Hanson, 25, and Chris Shaw, 24, did that with back-to-back pinch hit home runs to cap off a furious six-run Giants rally Monday, but their eighth-inning heroics werent enough to obscure the reality of the current state of affairs.

The Giants battled back from a five-run deficit to take a late lead, but the Rockies stormed back with two runs off Tony Watson in the eighth to down San Francisco 9-8 on Labor Day.

What a great comeback, its a shame we couldnt hold on, manager Bruce Bochy said. Because we fought hard. Really came on real strong there at the end. We just couldnt finish the job.

The air at Coors Field is thin, but the Giants odds of defeating the Rockies at the mile-high destination have appeared much thinner of late.

After Hanson launched a pinch-hit two-run homer off Rockies reliever Seunghwan Oh, Shaw slammed his first big league homer to push the Giants ahead 8-7.

Shaws 468-foot home run was the furthest by a Giants player this season and the first hit of his major league career. After producing a go-ahead sacrifice fly in his major league debut Friday, Shaw joined Aramis Garcia as the second Giants rookie in four games to crush a home run for his first career hit.

Thats the kind of thing you dream about, Shaw said. Your first knock being a home run and a go-ahead home run late in the ballgame. That was pretty surreal.

Shaw became the fourth player in San Francisco history to record his first major league hit on a pinch-hit home run and the first since Damon Minor did so September 10, 2000.

Im looking forward to watching him the rest of the year, starter Madison Bumgarner said.

Bumgarners command issues put the Giants in an early 4-0 hole, as D.J. LeMahieu and Trevor Story each hit two-run homers off the left-hander in the bottom of the first. Though he battled back to throw three scoreless innings, Bumgarner allowed a third home run in a start for the first time this season after an error extended the fifth.

With one-out, a hard-hit Nolan Arenado grounder skipped to the side of second base umpire Larry Vanover and right past the glove of second baseman Kelby Tomlinson, who could have stepped on the bag to start an inning-ending double play if he fielded the ball cleanly.

Instead, the Rockies had two on and one-out for Story, who became the fourth player to homer off of Bumgarner twice in the same game as he pushed the Rockies ahead 7-2 with a three-run shot to left field.

I didnt feel like my command was very good at all, Bumgarner said. Didnt feel like the stuff was super good either. The curveball felt pretty good, but everything else besides that I would like for it to be better. Especially here.

The Giants chipped away at the Rockies lead with a run in the sixth and two more in the seventh on a two-run triple from Evan Longoria, but they didnt overtake Colorado until the eighth. After Oh hit center fielder Gorkys Hernández with a pitch, Hanson lined his first home run since July 5 into the right field seats.

Hanny, look what he did, Bochy said. Thats huge to hit that home run and then Shaw got all of that one.

Since the Giants selected Shaw in the first round of the 2015 draft, hes showed off mammoth power and a skill set the franchise has lacked in recent years at the big league level.

After beginning his major league career with five strikeouts in his first six at-bats, Shaw finally connected on a hanging breaking ball and left no doubt.

Guys come in here and tell you to get ready, Shaw said of Coors Field. Its a show taking BP here and this is a place you get excited to come hit at.

Hanson and Shaw left the Giants optimistic about their potential, but an eight-run outburst from a struggling offense still wasnt enough to snap a dreadful stretch at Coors Field.

After the Rockies took a 9-8 lead against Watson, who has allowed eight earned runs in his last nine innings, the Giants struck out three times in the ninth to clinch their 16th loss in their last 18 games in Denver.

Belt day-to-day

Brandon Belt appeared as a defensive replacement in Mondays loss, but Bochy held his starting first baseman out of the lineup as Belt is dealing with right knee soreness.

Belt missed 17 games after hyperextending his knee running the bases July 25 and is still dealing with lingering effects from the injury. Bochy said Belt is day-to-day.